Embedding a non-embeddable stable plane

Abstract

In [4], K. Strambach describes a 2-dimensional stable plane R admitting Σ=SL2 R as a group of automorphisms such that there exists no Σ-equivarient embedding into a 2-dimensional projective plane. R. Löwen [3] has given a 4-dimensional analogue C, admitting Δ=SL2Copf. He posed the question whether there are embeddings of Strambach's plane R into C. We show that such embeddings exist, in fact we determine all -Σ-equivariant embeddings of 2-dimensional stable planes admitting Σ as atransitive group of automorphisms.